This invention relates to a process and apparatus for liquid-liquid counterflow extraction based on the mixer-separator principle, in which a dispersion of two liquid phases is fed to a separator and the clear phases are withdrawn from said separator.
It is known to use liquid-liquid counterflow extractors for a separation of two phases which are immiscible or difficultly miscible with each other. Such counterflow extractor consists usually of several stages, which are superimposed in a tower. For economical reasons, a small volumetric proportion of solvent, a short phase-separating time, and a large exchange surface area are desired (Verfahrenstechnik, 6th Year, No. 4, 1972, pages 123-128).
In these known extractors the dispersion to be separated is fed to a point at the periphery of the relatively low, circular separator and the separate phases are withdrawn on the opposite side. Where this procedure is adopted, the throughput rate per unit of bottom area, measured in m.sup.3 /m.sup.2 h, decreases as the diameter of the apparatus increases.